1. Field of the Invention
Exemplary embodiments of the present invention relates to a thin film transistor and a method of manufacturing a thin film transistor using an oxide semiconductor as an active layer.
2. Description of the Related Art
A liquid crystal display has been adopted as one of the most widely used displays. Typically, a liquid crystal display may include a display panel composed of two substrates, on which electrodes may be formed, and a liquid crystal layer may be interposed between the two substrates to display an image.
A plurality of pixel electrodes may be arranged in the form of a matrix on a first substrate of the two substrates, and a common electrode may be disposed on the whole surface of a second substrate of the two substrates. As voltages are separately applied to the respective pixel electrodes, an image is displayed on the display panel. To control a separate voltage applied to each pixel electrodes, thin film transistors may be connected to the respective pixel electrodes as elements for switching the voltages, and a plurality of interconnections including gate lines may be disposed to transfer signals for controlling the thin film transistors and data lines may be disposed to transfer the voltages to be applied to the pixel electrodes. In this example, the thin film transistor that is used as the switching element may include a gate electrode, source/drain electrodes, and an active layer, and when a predetermined voltage is s applied to the gate electrode, the active layer may be turned on to make current flow between the source electrode and the drain electrode.
On the other hand, since the liquid crystal display is a non-radiative device which has no self-luminous capability, a backlight unit for supplying light to the display panel should be provided. However, such light from the backlight unit is an important factor which acts as thermal stresses on the thin film transistors that render instabilities of the thin film transistors formed on the first substrate of the display panel by changing the characteristics of the thin film transistors.
Therefore, there is a need for an approach to provide a thin film transistor which has a structure capable of stably securing the characteristics of thin film transistors having a tolerance of the thermal influence of light even if the thin film transistors are irradiated with the light.